More about the BMI

Why the BMI is a BAD IDEA in Schools:

(excerpts from news reports)

If we're going to approach obesity from a legislative standpoint, let's use our government's energies to launch public health education campaigns and give parents some useful resources for treating the problem, such as information on how to shop for healthy foods and how to find ways to exercise with their children, rather than simple numbers and restatements of obesity/disease links. Placing BMIs on report cards does little to motivate parents or create solutions. (F is for Fat -- A Bad Idea)

Report cards are a place for reporting on school performance, not a child's characteristics or non-academic habits. There's a reason report cards include math, science, and English, not tooth-brushing, sleeping, and weight (despite their undoubted significance for a child's health). (F is for Fat -- A Bad Idea)

Just as a report card mark for "blood pressure" wouldn't give parents a complete picture of a child's health, neither does one only for BMI. (F is for Fat -- A Bad Idea)

Arkansas, which enacted a similar report card plan, is now considering dropping their BMI report cards after a lot of negative, unintended consequences and reports of damaged self-esteem. (F is for Fat -- A Bad Idea)

This plan might cause undue focus on body image, resulting in stress or even eating disorders, also a serious problem in schools. Most of us can remember times in school when comparing appearances lowered self-esteem; officially "grading" children on their bodies would likely be even more distressing. (F is for Fat -- A Bad Idea)

... because these measurements were done in school, elementary school children themselves were comparing themselves to one another – whispering about a girl who was 103 pounds, regardless of her height, and learning, oh, so young, to use numbers like weight and BMI as proxies not for health, but for self-worth, popularity, beauty, and desirability. (BMI In Schools: Educating Children in Loathing Not Health)

"1. The person who dreamed up the BMI said explicitly that it could not and should not be used to indicate the level of fatness in an individual.

2. It is scientifically nonsensical. There is no physiological reason to square a person's height (Quetelet had to square the height to get a formula that matched the overall data. If you can't fix the data, rig the formula!). Moreover, it ignores waist size, which is a clear indicator of obesity level.

3. It is physiologically wrong. It makes no allowance for the relative proportions of bone, muscle and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI. Thus, athletes and fit, health-conscious movie stars who work out a lot tend to find themselves classified as overweight or even obese."

"The BMI’s height and weight tables used to tell you what your score means came from the life insurance industry. Yep. A standardized table of average weights and heights was developed first in 1908, when life insurance companies began looking for ways to charge higher premiums to applicants based on screening by their own medical examiners. By setting the thresholds for “ideal weight” and “overweight” lower than what mortality data showed as the actual healthy weight ranges, they were able to collect more money for those they deemed “overweight.” In 1985, the NIH began defining obesity according to BMI, which defined the 85th percentile for each sex as the official cutoff for what constitutes “obese,” based on the standards for underweight, average, overweight and obese that were set by the 1983 Metropolitan Life Insurance Company mortality tables(Williamson, 1993)."

"Those same 1983 tables (and now our BMI) also failed to take gender into account, despite healthy levels of fat and weight distribution differing greatly between males and females (3)."

"BMI is based on a Caucasian standard. It is proven to be highly inaccurate for other races and ethnicities. In particular, in some Asian populations, a specific BMI reflects a higher percentage of body fat than in white or European Ppulations (James, 2002). Some Pacific populations and African Americans in general also have a lower percentage of body fat at a given BMI than do white or European populations (Stevens, 2002). Even the WHO has acknowledged the extensive evidence that “the associations between BMI, percentage of body fat, and body fat distribution differ across populations” (WHO, 2004)."